Mini-thoracoscopy vs Semirigid Thoracoscopy in Undiagnosed Exudative Pleural Effusions: A Randomized Controlled Trial

Background: Mini-Thoracoscope is a relatively newer rigid instrument for pleuroscopy and studies comparing its performance with other pleuroscopy instruments are lacking. This randomized trial compared “mini thoracoscopy” with Semi-Rigid thoracoscopy in undiagnosed pleural effusions. Methods: Consecutive subjects with undiagnosed exudative pleural effusion were randomized (1:1 ratio) to either of the two approaches, Mini-thoracoscopy (MT) or Semi-Rigid thoracoscopy (SRT). Procedures were performed under local anesthesia and combination moderate sedation. The primary outcome measure was the diagnostic yield between the two groups. Secondary outcomes were comparison of procedural pain, sedative doses, image quality, complications, and requirement of conversion to alternate equipment for pleural biopsy. Results: Fifty-six patients were randomized (29-MT and 27-SRT) and baseline characteristics were comparable. Diagnostic yield (MT-24/29, 82.8% and SRT-24/27, 88.9%, p=0.51) was similar between the groups. Operator rated pain, VAS (Visual analogue scale) (MT 45.0+17.8 and SRT 33.9+15.9, p=0.01) and patient rated pain, VAS (MT 44.6+18.1 and SRT 34.7+15.3, p=0.03) was greater in the MT group. Ease of maneuverability was better in the SRT group. Sedative doses, image quality, complications and ease of obtaining pleural biopsy were similar between the groups. Two patients in the MT group required conversion to SRT in view of difficulty in maneuverability. Conclusion: Mini-Thoracoscope has comparable diagnostic characteristics as compared to semirigid thoracoscopy in evaluation of undiagnosed pleural effusions but is associated with greater procedural discomfort.